Add get_column_styles for getting column structure and styles for a table

components/layout/fragment.rs

@@ -1408,6 +1408,16 @@ impl Fragment {
         }
     }
 
+    /// If this is a Column fragment, get the col span
+    ///
+    /// Panics for non-column fragments
+    pub fn column_span(&self) -> u32 {
+        match self.specific {
+            SpecificFragmentInfo::TableColumn(col_fragment) => max(col_fragment.span, 1),
+            _ => panic!("non-table-column fragment inside table column?!"),
+        }
+    }
+
     /// Returns true if this element can be split. This is true for text fragments, unless
     /// `white-space: pre` or `white-space: nowrap` is set.
     pub fn can_split(&self) -> bool {